Next in importance to Alfraganus among Dante’s authorities on astronomy was Aristotle. We have seen how overwhelming his authority became in natural science in the second half of the thirteenth century, and how for some time scholars failed to distinguish between the system of spheres devised by Eudoxus, which was the scheme upheld by Aristotle, and the epicycles and eccentrics of Ptolemy. Among all Aristotle’s admirers none was more devoted than Dante: for him Aristotle is not only “Il Filosofo,” the Philosopher _par excellence_, as he was generally called in that age; he is “quello glorioso filosofo al quale la Natura più aperse li suoi segreti,” his intellect was “quasi divino,” and his words are of “somma e altissima autoritade.”[98] Throughout Dante’s own writings his references to Aristotle are so frequent that Dr. Moore observes: “The amount and variety of Dante’s knowledge of the contents of the various works of Aristotle is nothing less than astonishing.”[99] ------------------------------------------------------------------------ [98] “That glorious philosopher to whom Nature most fully revealed her secrets,” _Conv._ III. v. 54-56; “almost divine,” _Conv._ IV. vi. 133; “supreme and highest authority,” _Ibid._ 52. [99] Moore, _Studies in Dante_ I. (Scripture and Classical Authors in Dante), from which much of the information in this chapter has been taken. ------------------------------------------------------------------------ He does not, however, consider Aristotle infallible as regards the details of astronomy, for in these the philosopher was only following the observers and mathematicians;[100] but in all matters which depend upon first principles, in which Dante would include the form of the earth, Aristotle’s authority may not be called in question.[101] In cosmical physics, such as the doctrine of the four elements, and in meteorology, Dante follows “il mio Maestro”[102] implicitly, and it is also largely from the _De Cælo_ that he gained his knowledge of early Greek speculations regarding the universe. ------------------------------------------------------------------------ [100] _Conv._ II. iii. 19-21. [101] _Conv._ III. v. 62-65. [102] “My master.” ------------------------------------------------------------------------